954-329-6647 This is another number claiming to be the IRS with a final notice of a lawsuit against you. It's a scam, here's an excerpt from the IRS warning about phone scams (irs.gov/uac/Newsroom/Phone-Scams-Continue-to-be-a-Serious-Threat,-Remain-on-IRS-Dirty-Dozen-List-of-Tax-Scams-for-the-2016-Filing-Season)
The IRS will never:
•Call to demand immediate payment, nor will the agency call about taxes owed without first having mailed you a bill.
•Demand that you pay taxes without giving you the opportunity to question or appeal the amount they say you owe.
•Require you to use a specific payment method for your taxes, such as a prepaid debit card.
•Ask for credit or debit card numbers over the phone.
•Threaten to bring in local police or other law-enforcement groups to have you arrested for not paying.